1. Field of the Invention
The present invention relates to a control apparatus for a vehicle lamp, a vehicle lighting system, and a vehicle lamp.
2. Related Art
Conventionally, there is known auto-leveling control which automatically adjusts an optical axis position of a vehicle headlamp to change an emitting direction in accordance with a tilt angle of a vehicle. In general, in the auto-leveling control, a vehicle height sensor is used as a tilt detection device for a vehicle, and an optical axis position of a headlamp is adjusted on the basis of a pitch angle of a vehicle detected by the vehicle height sensor. In contrast to this, Patent Document 1 discloses a configuration in which the auto-leveling control is performed by using a gravity sensor as the tilt detection device. In addition, Patent Document 2 discloses a configuration in which the auto-leveling control is performed by using a three-dimensional gyro sensor as the tilt detection device.
Patent Document 1: JP-A-2000-085459
Patent Document 2: JP-A-2004-314856
In the case where an acceleration sensor such as the gravity sensor or the three-dimensional gyro sensor is used as the tilt detection device for a vehicle, an auto-leveling system can be provided at lower cost than in the case where the vehicle height sensor is used, and a reduction in the weight thereof can also be achieved. On the other hand, even in the case where the acceleration sensor is used, there is a request for performing the auto-leveling control with enhanced precision by reducing a detection error of a tilt angle of a vehicle resulting from an attachment error of the sensor to the vehicle.